Cloud computing is computing in which large groups of remote servers are networked to allow centralized data storage, and online access to computer services or resources. It offers a new way of Information Technology (IT) services by rearranging various resources (e.g., storage, computing and services) and providing them to users based on their demands. Cloud computing provides a big resource pool by linking network resources together. It has desirable properties, such as scalability, elasticity, fault-tolerance, and pay-per-use. Thus, it becomes a promising service platform, rearranging the structure of IT.
Storage service is one of the most widely consumed cloud services. Nowadays, various data are stored at cloud, e.g., sensitive personal information, personal data, publicly shared data, limited shared data with a group of people and so on. Particularly, crucial data should be protected at the cloud to prevent from any access from unauthorized parties. Some unimportant data, however, has no such a demand. Thus, managing data storage at cloud in various situations in an efficient and flexible way is an important task for cloud service providers (CSP).
Further, for example, duplicated data may be stored at the cloud by the same users or different users, especially for shared data, in the same CSP or cross CSPs. Although cloud storage space is huge, this kind of duplication may greatly waste networking resources, consume a lot of power energy, increase operation cost, or make data management complicated. Thus, economic storage will greatly benefit CSPs by reducing operation cost and reversely benefit cloud users with reduced service fee.
In view of this, it would be advantageous to provide a way to allow for efficiently, flexibly and economically managing data storage in cloud computing.